JP2014009877A - Flue gas treatment equipment and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide flue gas desulfurization equipment and method for contriving effective utilization of waste heat of exhaust gas in a cleaning system for cleaning combustion exhaust gas to be exhausted from a boiler of a thermal power plant, etc., and effectively utilizing the exhaust gas.SOLUTION: In flue gas treatment equipment, a flow passage of exhaust gas from a boiler 1 is sequentially provided with: denitration equipment 2; an air preheater 3; a gas cooler 4; a dust collector 5; and desulfurizing equipment 7, the gas cooler 4 is provided with a heat medium circulation line 29 with a heat medium flow rate control valve 19, a heat medium bypass line 30 for circulating a heat medium between the gas cooler 4 and a binary power generating facility 17 which utilizes heat of the exhaust gas collected by the line 29, by bypassing the binary power generating facility 17, a control valve 19, and the cooler 4 is connected to the heat medium circulation line 29, and a supply amount of the heat medium in the heat medium circulation line 29 to be supplied to the cooler 4 and a supply amount of a heat medium in the bypass line 30 are controlled according to exhaust gas temperature at an outlet of the cooler 4 so that the exhaust gas temperature at the outlet of the cooler 4 becomes a predetermined value.

Description

  The present invention relates to a flue gas treatment apparatus and method for purifying exhaust gas discharged from combustion equipment such as a boiler installed in a thermal power plant or factory, and effectively uses waste heat from the combustion equipment such as a boiler. The present invention relates to a smoke treatment apparatus and method that have a binary power generation facility and can perform stable operation while generating power using waste heat.

  As a waste heat recovery means for exhaust gas discharged from a boiler or the like, FIG. 5 shows a system in which a gas cooler is provided in an exhaust gas system from a boiler and has a binary power generation facility. In each figure, the same number is assigned to the same device.

  In FIG. 5, exhaust gas discharged from a boiler 1 or the like installed in a thermal power plant or factory flows into a dust collector 5 through a denitration device 2 and a boiler air preheater 3. After removing dust from the exhaust gas flowing into the dust collector 5, the exhaust gas is pressurized by the exhaust gas fan 6 and introduced into the absorption tower 7. Thereafter, the exhaust gas passes through the waste heat recovery heat exchanger 8 and is finally discharged from the chimney 9 into the atmosphere. The waste heat recovery heat exchanger 8 is connected by a binary power generation turbine 11 and a pipe 12 so as to form a closed loop.

  Here, the dust contained in the exhaust gas discharged from the boiler 1 or the like is removed by the dust collector 5 and then flows into the absorption tower 7. In the absorption tower 7, the absorption liquid circulates in the absorption tower, and acidic gases such as sulfur oxides, hydrogen chloride, and hydrogen fluoride in the exhaust gas are removed by gas-liquid contact with the exhaust gas. Here, in the absorption tower 7, the exhaust gas is lowered to the saturated gas temperature by gas-liquid contact with the absorption liquid, and the exhaust gas discharged from the absorption tower 7 generally has a temperature of about 50 ° C.

  For example, an indirect heat exchanger is used as the heat exchanger 8 for waste heat recovery, and the heat exchange medium flowing in the heat exchanger 8 for waste heat recovery is evaporated by bringing it into indirect contact with the exhaust gas from the outlet of the absorption tower 7. Let The heat exchange medium evaporated here is further heated to superheated steam through the binary power generation facility circulation line 12, for example, using the extraction of the steam line 13 obtained by the power generation boiler in the vapor heater 26, and becomes superheated steam. The steam is supplied to the binary power generation turbine 11 and used by the generator 27. The heat exchange medium that has passed through the binary power generation turbine 11 is sent to the condenser 14, where cooling water such as seawater is cooled and condensed by the water line 15 or the like, and is passed through the binary power generation equipment circulation pipe 12. After being boosted by the binary power generation heat medium circulation pump 16, it again flows into the waste heat recovery heat exchanger 8.

FIG. 6 shows the configuration of an exhaust gas treatment system from another prior art boiler 1 or the like.
In FIG. 6, the exhaust gas discharged from the boiler 1 or the like is introduced into the denitration device 2, and after nitrogen oxides in the exhaust gas are removed, the boiler air preheater 3 exchanges heat with the combustion air sent to the boiler 1. The Next, after exhaust gas is introduced into the gas cooler 4 and cooled, it is introduced into the electrostatic precipitator 5 to remove most of the dust in the exhaust gas. Thereafter, the exhaust gas is pressurized by the exhaust gas fan 6 and introduced into the absorption tower 7, and acid gases such as sulfur oxide, hydrogen chloride, and hydrogen fluoride in the exhaust gas are removed by gas-liquid contact. The exhaust gas cooled to the saturated gas temperature in the absorption tower 7 is then heated by the gas reheater 10 using the waste heat recovered in the gas cooler 4 and discharged from the chimney 9 into the atmosphere.

  The gas cooler 4 and the gas reheater 10 are connected in a closed loop by piping, and hot water circulates using the inside as a medium. The medium heated by the gas cooler 4 flows into the gas reheater 10, the temperature is lowered by heat exchange with the low temperature gas at the outlet of the absorption tower 7, and flows into the gas cooler 4 again.

  As described above, as a means for recovering the waste heat of the exhaust gas discharged from the boiler 1 or the like, for example, the waste heat recovery heat exchanger 8 is installed in the outlet exhaust gas flue of the absorption tower 7 shown in FIG. A system itself that uses the recovered heat as a heat source of the binary power generation facility 17 is known, and has been proposed in, for example, Japanese Patent Laid-Open No. Hei 6-26310.

  Further, a technique for reusing heat recovered by the gas cooler 4 shown in FIG. 6 for reheating exhaust gas by the gas reheater 10 installed at the outlet of the absorption tower 7 is known and has already been put into practical use. .

  In addition, the preheated heat medium is used for pre-heating the exhaust gas discharged from the power generation system using the heat medium indirectly heated by the steam generated from the low-grade coal dryer that is indirectly heated by the latent heat of the superheated steam. Japanese Patent Application Laid-Open No. 2011-214559 discloses a technique for effectively using the power generation and improving the power generation efficiency more than ever.

  Further, in Japanese Patent Laid-Open No. 5-18212, hot water fed from a hot water pump is passed through a hot water system to the primary side of a plurality of preheaters, and a medium flowing to the secondary side of the plurality of preheaters is used as hot water. In which the medium flowing to the secondary side of the preheater is condensed by the condenser through which the cooling water flows and circulated to the medium pump. It is described that the flow rate of the heat source that flows on the primary side of the preheater is adjusted by a control valve so that the detection value of the temperature detector provided in is a specified value.

JP-A-6-26310 JP2011-214559A JP-A-5-18212

  In the prior art shown in FIG. 5 above, the exhaust gas at the inlet of the heat exchanger 8 for waste heat recovery is relatively low temperature, so the bleed air 13 from the power generation boiler is used to further raise the temperature of the heat exchange medium. There was a problem that the plant efficiency deteriorated. Moreover, it has not led to the performance improvement of the flue gas processing apparatus itself discharged | emitted from the boiler 1 grade | etc.,.

  Moreover, although the technique which utilizes the heat | fever collect | recovered with the gas cooler 4 shown in FIG. 6 for the reheating of waste gas with the gas reheater 10 installed in the exit of the absorption tower 7 is already put into practical use, the absorption tower 7 The outlet gas is a corrosive gas, and the material used for the gas reheater 10 needs to select an expensive material in consideration of the corrosion resistance, resulting in an increase in equipment cost.

  Furthermore, the above-mentioned Patent Document 2 discloses a technique for effectively using a heat medium preheated by steam generated in a low-grade coal drying system for power generation in a binary cycle, and improving power generation efficiency more than before. This technology is not used in a flue gas purification treatment system. Further, in the above technical document 3, it is disclosed that the flow rate of the heating medium to the preheater is adjusted according to the temperature of the heating medium supplied to the heating medium turbine. This technique is also used in the exhaust gas purification processing system. It is not something that can be done.

  An object of the present invention is to effectively use waste heat of exhaust gas in a purification system for purifying combustion exhaust gas discharged from a boiler or the like of a thermal power plant and to effectively use the exhaust gas. Is to provide.

The above-mentioned problem of the present invention is solved by the following means.
The invention described in claim 1 includes a denitration device (2), a combustion device air preheater (3), gas cooling from the upstream side to the downstream side of the exhaust gas flow channel for flowing exhaust gas discharged from the combustion device (1). In a flue gas treatment device provided with a vessel (4), a dust collector (5) and a desulfurization device (7) in sequence,
The gas cooler (4) is provided with a heat medium circulation line (29) for recovering the heat of the exhaust gas discharged from the combustion device (1), and the exhaust gas recovered by the heat medium circulation line (29) is disposed. The binary power generation facility (17) using heat is connected to the heat medium circulation line (29), and the heat medium temperature is measured at the inlet and outlet of the binary power generation facility (17) of the heat medium circulation line (29). Temperature measuring means (24a, 24b) is provided, and a temperature measuring means (21) for measuring the exhaust gas temperature at the outlet of the gas cooler (4) is provided in the exhaust gas passage at the outlet of the gas cooler (4), A heat medium flow control valve (19) is provided at the inlet of the gas cooler (4) of the heat medium circulation line (29), and bypasses the heat medium flow control valve (19) and the gas cooler (4). A heat medium that circulates between the binary power generation equipment (17) Condenser heat medium bypass line (30) is a flue gas treatment apparatus, characterized in that connected to the heat medium circulation line (29).

  The invention according to claim 2 is a binary power generation equipment heat medium circulation line (23) that circulates the heat medium to the binary power generation equipment (17) bypassing the gas cooler heat medium bypass line (30) and the gas cooler (4). ) Is connected to the heat medium circulation line (29), and from the connection point of the heat medium circulation line (29) connected to the binary power generation facility heat medium circulation line (23), the heat medium circulation line ( 29. The flue gas treatment apparatus according to claim 1, wherein a heat medium flow control valve (22) is provided in 29).

  Invention of Claim 3 has arrange | positioned the heat exchanger (25) for heat-medium temperature adjustment which has a cooling water supply line (15) and a steam supply line (13) in the heat-medium circulation line (29). The smoke processing apparatus according to claim 2.

  According to the invention of claim 4, according to the exhaust gas temperature at the outlet of the gas cooler (4), the exhaust gas temperature at the outlet of the gas cooler (4) in the exhaust gas treatment device according to claim 1 becomes a predetermined value. Drainage characterized by controlling the supply amount of the heat medium in the heat medium circulation line (29) supplied to the gas cooler (4) and the supply amount of the heat medium in the gas cooler heat medium bypass line (30). Smoke treatment method.

  According to a fifth aspect of the present invention, the exhaust gas temperature at the outlet of the gas cooler (4) and / or the heat medium temperature at the inlet or outlet of the binary power generation facility (17) in the flue gas treatment apparatus according to the second aspect is a predetermined value. The heat medium circulation to be supplied to the gas cooler (4) according to the exhaust gas temperature at the outlet of the gas cooler (4) and / or the heat medium temperature at the inlet or outlet of the binary power generation facility (17) A flue gas treatment method characterized by controlling the supply amount of the heat medium in the line (29) and / or the heat medium amount in the heat medium circulation line (23) of the binary power generation facility supplied to the binary power generation facility (17). It is.

  In the invention described in claim 6, the exhaust gas temperature at the outlet of the gas cooler (4) and / or the temperature of the heat medium at the inlet or outlet of the binary power generation facility (17) in the flue gas treatment apparatus according to claim 3 is a predetermined value. The heat medium circulation to be supplied to the gas cooler (4) according to the exhaust gas temperature at the outlet of the gas cooler (4) and / or the heat medium temperature at the inlet or outlet of the binary power generation facility (17) The amount of water supplied to the heat exchanger (25) for controlling the heat medium supply amount in the line (29) and / or the heat medium supply amount to the binary power generation facility (17) or the heat medium temperature adjustment or It is a flue gas treatment method characterized by adjusting the amount of steam.

(Function)
In general, the dust collection performance of an electrostatic precipitator is determined by a number of factors such as dust particle size, dust composition, dust electrical resistance, and the amount of charge in the electrostatic precipitator. Depends on the specific characteristics of the fuel such as coal used. On the other hand, the electrical resistance value of the dust varies depending on the operating temperature and the like, and in the general operating temperature range of the electrostatic precipitator, the dust collection performance of the electrostatic precipitator is improved by the decrease of the electrical resistance value.

  FIG. 3 shows an example of the correlation between the gas temperature in the electrostatic precipitator and the electrical resistance value of the soot contained in the exhaust gas (the numerical value varies depending on the coal type). In such an operating temperature range, the electric resistance value of the dust decreases due to the decrease in the gas temperature, and thereby the dust collection performance in the electric dust collector is improved as compared with the case where the gas temperature is high.

  However, if the gas temperature at the inlet of the electrostatic precipitator decreases, there is a problem that the dust inside the electrostatic precipitator becomes stuck, clogged, and it becomes difficult to transport the collected ash. It is necessary to operate at a temperature of 80 ° C to 85 ° C or higher.

  FIG. 4 shows an example of the correlation between the heat medium temperature, which is an external heat source in the binary power generation facility, and the power generation amount (the numerical value varies depending on the coal type). The higher the temperature of the external heat source supplied to the binary power generation facility, the larger the amount of power generation and the more efficient use of waste heat.

  Although depending on the characteristics of the heat exchange medium circulating in the binary power generation facility, it is desirable to supply the heat medium as the external heat source at a temperature of, for example, 80 ° C. to 120 ° C., and the heat medium temperature is about 80 ° C. or less. Then, the evaporation efficiency of the heat exchange medium circulating in the binary power generation facility is poor, and it is necessary to stop the operation of the facility. On the other hand, when the external heat medium temperature is about 120 ° C. or higher, problems such as decomposition of the heat exchange medium circulating in the binary power generation facility occur, and it is necessary to stop the operation of the binary power generation facility.

  As a means to recover waste heat of exhaust gas discharged from boilers, etc., a system with a gas cooler installed upstream (front side) of the electrostatic precipitator and a heat medium circulation line that circulates through the binary power generation facility In the configuration, the amount of heat medium to be supplied to the gas cooler and the binary power generation facility according to the gas cooler outlet gas temperature (electric dust collector inlet gas temperature) employed in the present invention and the heat medium temperature in the heat medium circulation system By adopting a controllable configuration, it is possible to stably operate a high-performance and energy-saving system by improving the performance of the smoke treatment apparatus itself and effectively using waste heat.

  According to the first and fourth aspects of the invention, the gas cooler 4 is sent to the gas cooler 4 in accordance with the exhaust gas temperature at the outlet of the gas cooler 4 so that the exhaust gas temperature at the outlet of the gas cooler 4 in the smoke treatment apparatus becomes a predetermined value. Since the supply amount of the heat medium in the heat medium circulation line 29 to be supplied and the supply amount of the heat medium in the gas cooler heat medium bypass line 30 can be controlled, the exhaust gas discharged from the combustion apparatus such as the boiler 1 can be controlled. Power generation by effective use of waste heat can be performed while sufficiently satisfying environmental regulations and environmental equipment performance, and high smoke treatment performance and stable operation of an energy-saving system are possible.

  According to the second and fifth aspects of the present invention, the outlet of the gas cooler 4 is adjusted so that the exhaust gas temperature at the outlet of the gas cooler 4 and / or the heat medium temperature at the inlet or outlet of the binary power generation facility 17 becomes a predetermined value. The heat medium supply amount and / or the binary power generation equipment 17 in the heat medium circulation line 29 supplied to the gas cooler 4 in accordance with the exhaust gas temperature and / or the heat medium temperature at the inlet or outlet of the binary power generation equipment 17. Since the amount of heat medium in the binary power generation facility heat medium circulation line 23 supplied to the power source can be controlled, in addition to the effects of the first and fourth aspects of the invention, more accurate high smoke treatment performance and energy-saving system Stable operation is possible.

  More specifically, when the temperature of the heat medium in the heat medium circulation line 29 is not sufficiently high at the time of starting the combustion apparatus such as the boiler 1, or when the binary power generation equipment 17 is defective, the heat medium flow control valve 22 is used. Is closed to prevent the heat medium from flowing into the binary power generation facility 17, and when the temperature of the heat medium at the outlet of the binary power generation facility 17 is too low, the binary power generation facility 17 is adjusted by adjusting the opening of the heat medium flow control valve 22. It is possible to adjust the amount of heat medium flowing into the.

  According to the third and sixth aspects of the present invention, the gas cooler 4 outlet is set so that the exhaust gas temperature at the outlet of the gas cooler 4 and / or the heat medium temperature at the inlet or outlet of the binary power generation equipment 17 becomes a predetermined value. The heat medium supply amount and / or the binary power generation equipment 17 in the heat medium circulation line 29 supplied to the gas cooler 4 in accordance with the exhaust gas temperature and / or the heat medium temperature at the inlet or outlet of the binary power generation equipment 17. The amount of water or steam supplied to the heat exchanger 25 for adjusting the temperature of the heating medium is adjusted or the amount of water or steam supplied to the heat exchanger 25 for adjusting the temperature of the heating medium is adjusted. Well, high smoke removal performance and stable operation of energy saving system are possible.

It is a lineblock diagram showing the flue gas processing device which provided the heat carrier circulation line which circulates the gas cooler and binary power generation equipment which become one example of the present invention. It is a lineblock diagram showing the flue gas processing device which provided the heat carrier circulation line which circulates the gas cooler and binary power generation equipment which become one example of the present invention. It is a figure which shows an example of the correlation of the gas temperature in the electric dust collector which becomes one Example of this invention, and the electrical resistance value of the dust in exhaust gas. It is a figure which shows an example of the correlation of the heat-medium temperature used as an external heat source, and power generation amount in the binary power generation equipment which becomes one Example of this invention. It is the block diagram which provided the waste heat recovery heat exchanger and the binary power generation equipment in the exhaust gas system from a boiler as a means to perform the waste heat recovery of the exhaust gas discharged | emitted from a boiler etc. in a prior art. An example of providing a gas cooler in an exhaust gas system from a boiler as a means for performing waste heat recovery of exhaust gas discharged from a boiler or the like in the prior art, and using the recovered heat for reheating the gas at the absorption tower outlet FIG.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a gas cooler 4 provided in an exhaust gas flow path from the boiler 1 as means for recovering waste heat of exhaust gas discharged from a combustion apparatus such as a boiler, and has a binary power generation facility 17. In the system configuration provided with the heat medium circulation line 29 that circulates through the binary power generation equipment 17, the amount of the heat medium that is circulated according to the outlet gas temperature of the gas cooler 4 and the heat medium temperature in the heat medium circulation line 29 can be controlled. The example regarding the possible equipment configuration and its flow control (operation) is shown.

  Exhaust gas discharged from a boiler 1 installed in a thermal power plant or factory is introduced into a gas cooler 4 through a denitration device 2 and a boiler air preheater 3. The exhaust gas whose gas temperature has decreased in the gas cooler 4 is introduced into the electrostatic precipitator 5, and the dust in the exhaust gas is removed. Thereafter, the exhaust gas is pressurized by the exhaust gas fan 6 and finally discharged from the chimney 9 through the absorption tower 7.

  Further, the gas cooler 4 and the binary power generation equipment 17 are connected in a closed loop by a heat medium circulation line 29 through which the heat medium circulates, and a gas cooler heat medium circulation pump 18 is connected to the heat medium circulation line 29. Provided. Further, a heat medium flow control valve 19 is provided on the inlet side of the gas cooler 4 of the heat medium circulation line 29, and gas cooling that bypasses the heat medium flow control valve 19 and the gas cooler 4 is further provided in the heat medium circulation line 29. An apparatus heat medium bypass line 30 is provided, and the gas cooler heat medium bypass line heat medium flow control valve 20 is disposed.

  The heat medium flow rate control valve 19 and the gas cooler heat medium bypass line heat medium flow rate control valve 20 are used to control the heat medium supply amount from the heat medium circulation line 29 to the gas cooler 4. Heat medium circulation thermometers 24a and 24b are provided in the heat medium circulation lines 29 on the inlet side and the outlet side of the binary power generation facility 17, respectively.

  In the prior art shown in FIG. 5, since the exhaust gas temperature at the inlet of the waste heat recovery heat exchanger 8 is relatively low, it is necessary to use the bleed air 13 from the power generation boiler 1 to further increase the temperature of the heat exchange medium. There was a problem that the plant efficiency deteriorated. Moreover, it has not led to the performance improvement of the flue gas processing apparatus itself discharged | emitted from the boiler 1 grade | etc.,.

  The exhaust gas temperature discharged from the boiler 1 or the like installed in a thermal power plant or factory differs depending on the fuel used, but in the case of a coal-fired boiler, normally at the inlet of the electrostatic precipitator 5 is 120 ° C to It is a relatively high temperature of 160 ° C. As shown in FIG. 3, the dust collection performance of the electric dust collector 5 shows a correlation between the operating temperature and the electric resistance value of the dust, and the electric resistance value of the dust is reduced by lowering the gas temperature. The dust collection performance at 5 is improved.

  Further, in the binary power generation facility 17 illustrated in FIG. 1, although depending on the characteristics of the heat exchange medium circulating in the binary power generation facility 17, the heat medium that is an external heat source is, for example, at a temperature of 80 ° C. to 120 ° C. It is desirable to supply, and it is effective to install the gas cooler 4 at the inlet of the electrostatic precipitator 5 and use the heat recovered here as a heat source of the binary power generation equipment 17.

  In FIG. 1, exhaust gas discharged from a boiler 1 or the like installed in a thermal power plant or factory is introduced into a gas cooler 4 through a denitration device 2 and a boiler air preheater 3. The gas cooler 4 is composed of, for example, a multi-tube heat exchanger, and has a structure in which exhaust gas flows on the outer surface of the tube and a heat medium (internal heat medium) flows on the inner surface of the tube. The gas temperature is lowered by heat exchange with the heat medium flowing on the inner surface of the tube, and is introduced into the electrostatic precipitator 5 to remove dust in the exhaust gas.

  The gas cooler 4 and the binary power generation equipment 17 are connected by a heat medium circulation line 29. The heat medium circulation line 29 is provided with a gas cooler heat medium circulation pump 18, and industrial water is circulated by circulating the heat medium in a closed loop. It is not necessary to continuously use a heat medium such as industrial water, and industrial water is used as the heat medium, so that the heat exchanger and the heat medium circulation line 29 of the gas cooler 4 should use inexpensive carbon steel materials. Can do.

  In the gas cooler 4, the waste heat of the exhaust gas from the boiler 1 or the like is recovered. However, when the inlet gas temperature of the electrostatic precipitator 5 decreases to a certain value or less, the dust is fixed in the electrostatic precipitator 5 and There are problems such as difficulty in transporting the dust collected by the electric dust collector 5.

  The amount of exhaust gas discharged from the boiler 1 or the like and the temperature of the exhaust gas fluctuate depending on the operation state of the power generation equipment such as the boiler 1. Therefore, when the amount of the heat medium to the gas cooler 4 is not controlled, the outlet of the gas cooler 4 The exhaust gas temperature becomes a desired temperature according to the amount of exhaust gas. By controlling the amount of circulation of the heat medium supplied to the gas cooler 4, the exhaust gas temperature (measured by the thermometer 21) at the outlet of the gas cooler 4 can be maintained at a predetermined value, and the stable operation of the flue gas treatment apparatus can be achieved. It becomes possible. That is, when the exhaust gas temperature at the outlet of the gas cooler 4 becomes a predetermined value or less, the ash cannot be fixed or the ash is transported (dispensed) by the ash wetting in the electrostatic precipitator 5, and Since the operation becomes difficult, it is necessary to keep the exhaust gas temperature at the outlet of the gas cooler 4 at a predetermined value so that this is not the case.

  Further, in addition to these facilities, the gas cooler heat medium circulation pump 18 provided in the heat medium circulation line 29 can be variable in flow rate, or a plurality of pumps 18 can be installed to The operation of controlling the amount of the heat medium flowing through the whole according to the outlet gas temperature of the gas cooler 4 is also an effective means.

  The heat medium heated by the gas cooler 4 by indirect contact with the waste heat of the boiler 1 or the like is supplied to the binary power generation facility 17 and used as a heat source for the binary power generation facility 17, and then the heat medium whose temperature has decreased. Is supplied to the gas cooler 4 by the gas cooler heat medium circulation pump 18.

FIG. 2 shows another embodiment of the present invention. The equipment and members shown in FIG. 2 that have the same functions as the equipment and members shown in FIG.
The amount of exhaust gas discharged from the boiler 1 or the like and the temperature of the exhaust gas fluctuate depending on the operation state of the plant power generation equipment such as the boiler 1, so the temperature was raised by indirect contact with the waste heat of the boiler 1 or the like by the gas cooler 4. The heat medium temperature also varies depending on the operating state of the plant power generation equipment such as the boiler 1.

  As described above, although depending on the characteristics of the heat exchange medium circulating in the binary power generation facility 17, the heat medium temperature as an external heat source is desirably supplied at a temperature of, for example, 80 ° C. to 120 ° C. When the temperature is about 80 ° C. or lower, the evaporation performance of the heat exchange medium circulating in the binary power generation facility 17 is poor, and it is necessary to stop the operation of the facility. On the other hand, when the external heat medium temperature is about 120 ° C. or higher, problems such as decomposition of the heat exchange medium occur, and it is necessary to stop the operation of the facility.

  In FIG. 2, in a system configuration provided with a heat medium circulation line 29 that circulates between the gas cooler 4 and the binary power generation facility 17, the heat medium circulation line 29 on the inlet side of the binary power generation facility 17 and the outlet of the binary power generation facility 17. Between the heat medium circulation line 29 on the side, a binary power generation facility heat medium bypass line 23 that bypasses the gas cooler 4 is provided. The binary power generation facility heat medium bypass line 23 is arranged in parallel with the gas cooler heat medium bypass line 30, but the binary power generation facility 17 is closer to the binary power generation facility 17 than the gas cooler heat medium bypass line 30. Are connected to the respective heat medium circulation lines 29 on the inlet side and the outlet side.

  Further, a heat medium flow control valve 22 is provided in the heat medium circulation line 29 closer to the binary power generation facility 17 inlet than the connection point between the binary power generation facility heat medium circulation line 23 and the heat medium circulation line 29, and further the binary power generation facility heat medium. A heat medium flow rate control valve 32 is provided in the bypass line 23 so that the heat medium supply amount to the binary power generation facility 17 can be controlled.

By providing the heat medium flow control valve 22 and the binary power generation facility heat medium bypass line 23, the following functions are achieved. Ie
(1) When the boiler is started up, the exhaust gas temperature at the outlet of the boiler 1 is low and the boiler waste heat cannot be recovered. Therefore, the temperature of the heat medium in the gas cooler 4 is low, and there is no point in supplying the binary power generation equipment 17 with a heat medium. In such a case, the heat medium flow control valve 22 is closed and the binary power generation facility 17 is bypassed using the binary power generation facility heat medium bypass line 23 to circulate the heat medium.

(2) Even when a failure occurs in the binary power generation facility 17, the heat medium flow control valve 22 can be closed to continue the operation of the smoke treatment apparatus.
(3) When the temperature of the heat medium temperature at the outlet of the binary power generation facility 17 (measured by the heat medium thermometer 24b) becomes too low, the amount of heat medium (bypass amount) to the binary power generation facility 17 is controlled by the heat medium flow rate. It can be easily adjusted by opening / closing control of the valve 22.

  The heat medium circulation line 29 is provided with a heat exchanger 25 for controlling the temperature of the heat medium. The heat exchanger 25 for controlling the temperature of the heat medium is cooled with the steam line 13 and the heat medium for cooling the temperature of the heat medium. A water line 15 is connected for use.

  In place of the water line 15 connected to the heat exchanger 25 for controlling the heat medium temperature, a line (not shown) for supplying water directly to the heat medium circulation line 29 on the inlet side of the binary power generation facility 17 is connected. A line (not shown) for discharging water from the heat medium circulation line 29 on the outlet side of the binary power generation facility 17 may be connected.

  Here, when the inlet heat medium temperature of the binary power generation equipment 17 becomes about 80 ° C. or less, for example, steam is supplied to the heat medium temperature control heat exchanger 25 from the steam line 13, and the binary power generation equipment 17 Operation is possible by raising the temperature of the heat medium to a temperature suitable for operation. In addition, in the case where it is difficult to supply steam from the outside or to reduce the steam supply amount, stopping the supply of the heat medium to the binary power generation equipment 17 is one means. In such a case, the gas cooler 4 Thus, there is no means for lowering the temperature of the heating medium heated in step 1, the gas temperature in the gas cooler 4 cannot be lowered, and the inlet gas temperature of the electrostatic precipitator 5 is increased. As described above, since the dust collection performance of the electric dust collector 5 depends on the gas temperature, there is a problem that the required dust removal performance cannot be satisfied.

  In the equipment configuration shown in FIG. 2, the heat medium circulation line 29 is provided with a heat exchanger temperature control heat exchanger 25, and water is supplied from the water line 15 to the heat medium temperature control heat exchanger 25. The heat medium temperature supplied to the gas cooler 4 can be reduced to a predetermined value or less, and the environmental regulation value of the exhaust gas discharged from the boiler 1 or the like is satisfied regardless of whether or not the binary power generation facility 17 is operated. Stable operation is possible.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Denitration apparatus 3 Boiler air preheater 4 Gas cooler 5 Electric dust collector 6 Exhaust gas fan 7 Absorption tower 8 Waste heat recovery heat exchanger 9 Chimney 10 Gas reheater 11 Binary power generation turbine 12 Piping 13 Steam line 14 condenser 15 water line 16 binary power generation heat medium circulation pump 17 binary power generation equipment 18 heat medium circulation pump 19, 22 heat medium circulation line heat medium flow control valve 20 gas cooler heat medium bypass line heat medium flow control valve 21 exhaust gas thermometer 23 Binary power generation facility heat medium bypass lines 24a, 24b Heat medium circulation thermometer 25 Heat exchanger for heat medium temperature control 26 Vapor heater 27 Generator 29 Heat medium circulation line 30 Gas cooler heat medium bypass line 32 Binary power generation facility heat Medium bypass line Heat medium flow control valve

Claims (6)

In a flue gas treatment apparatus in which a denitration apparatus, an air preheater for a combustion apparatus, a gas cooler, a dust collecting apparatus, and a desulfurization apparatus are sequentially provided from the upstream side to the downstream side of an exhaust gas flow channel for flowing exhaust gas discharged from the combustion apparatus. ,
The gas cooler is provided with a heat medium circulation line that recovers the heat of the exhaust gas discharged from the combustion device, and a binary power generation facility that uses the heat of the exhaust gas recovered by the heat medium circulation line serves as a heat medium circulation line. Connected to
Provided with temperature measuring means for measuring the temperature of the heating medium at the inlet and outlet of the binary power generation facility of the heating medium circulation line,
The exhaust gas passage at the outlet of the gas cooler is provided with a temperature measuring means for measuring the exhaust gas temperature at the outlet of the gas cooler,
A gas cooling system in which a heat medium flow control valve is provided at the gas cooler inlet of the heat medium circulation line, and the heat medium is circulated between the binary power generation equipment by bypassing the heat medium flow control valve and the gas cooler. A flue gas treatment apparatus, wherein the heat exchanger bypass line is connected to the heat medium circulation line.   Connect the heat generating medium circulation line to the binary power generation facility, bypassing the gas cooler heat medium bypass line and the gas cooler, and connect to the binary power generation facility heat medium circulation line. The flue gas treatment apparatus according to claim 1, wherein a heat medium flow control valve is provided in the heat medium circulation line on the binary power generation facility inlet side from a connection point of the heat medium circulation line to be operated.   The exhaust gas processing apparatus according to claim 2, wherein a heat exchanger for adjusting the temperature of the heat medium having a cooling water supply line and a steam supply line is arranged in the heat medium circulation line.   The heat medium in the heat medium circulation line supplied to the gas cooler according to the exhaust gas temperature at the gas cooler outlet so that the exhaust gas temperature at the gas cooler outlet in the smoke treatment apparatus according to claim 1 becomes a predetermined value. The flue gas treatment method is characterized by controlling the supply amount of the heat medium and the supply amount of the heat medium in the gas cooler heat medium bypass line.   The exhaust gas temperature at the gas cooler outlet and / or the exhaust gas temperature at the gas cooler outlet and / or the heat medium temperature at the inlet or outlet of the binary power generation facility in the exhaust gas treatment apparatus according to claim 2. Alternatively, depending on the temperature of the heat medium at the inlet or outlet of the binary power generation facility, the supply amount of the heat medium in the heat medium circulation line supplied to the gas cooler and / or the binary power generation facility heat medium circulation supplied to the binary power generation facility A flue gas treatment method characterized by controlling the amount of heat medium in the line.   The exhaust gas temperature at the outlet of the gas cooler and / or the exhaust gas temperature at the outlet of the gas cooler and / or the heat medium temperature at the inlet or outlet of the binary power generation facility in the exhaust gas treatment apparatus according to claim 3 Alternatively, the supply amount of the heat medium in the heat medium circulation line supplied to the gas cooler and / or the supply amount of the heat medium to the binary power generation facility is controlled according to the heat medium temperature at the inlet or outlet of the binary power generation facility. Or adjusting the amount of water or steam supplied to the heat exchanger for adjusting the temperature of the heat medium.

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